Process for heat treating travelling linear material



Nov. 10, 1970 N. w. HAYMAN 3,539,663,

PROCESS FOR HEAT TREATING TRAVELLING LINEAR MATERIAL Filed May 9, 1968 I nvenlor [W42 fiez 52,444

%M "/daw Attorneys United States Patent O US. Cl. 264-80 4 Claims ABSTRACT OF THE DISCLOSURE A process and apparatus for providing a uniform heat treatment to travelling linear material wherein the material is passed longitudinally through and along a gaseous flame in the direction of flame propagation to dis tribute heat uniformly around the material and to uniformly heat the material.

The invention is concerned with improvements in or relating to the heat treatment of travelling linear material. Particularly, but not exclusively, it is concerned with such heat treatment of travelling textile materials, as for instance fabrics and yarns, especially those made of synthetic materials.

BACKGROUND OF THE INVENTION It is often required to provide travelling linear material with a uniform heat treatment, so as to bring about a desired physical change in the material uniformly therethrough.

Subject to the attainment of the required level of uniformity, it is clear that the economics of the process demand the highest throughput of treated material, i.e. the greatest weight of treated material per unit time.

The normal methods for heating travelling yarns and fabrics are to pass them linearly in contact with heated rolls or plates or through ovens supplied with steam, hot air, etc.

It is also known to pass a travelling yarn or fabric in the vicinity of a radiating body, such as an electric arc.

Further, flame treatment of yarns and fabrics are known for the purpose of singeing them, or for creating a temperature gradient across tensioned filaments so that after relaxation the filaments will crimp due to differential stress.

It will be appreciated that the throughput of the above referred to processes for uniformly heating travelling yarns and fabrics is limited by the rate of heat transfer possible between their material and the heated gas or the heated body near, or in contact with, which they are caused to travel.

Likewise, it will be appreciated that flame treatments of yarns and fabrics have not been known for the purposes of uniformly heating them.

SUMMARY OF THE INVENTION According to the invention, a process for providing a uniform heat treatment to travelling linear material com prises passing said material longitudinally through and along a gaseous flame.

By this means the high thermal efliciency of a gaseous flame is utilised in a manner to provide uniform heat treatment, for instance a heat-relaxation treatment for continuous filament yarns, such as those of nylon after drawing and prior to wind-up.

Naturally, the rate of travel of the linear material must need be high enough to avoid damage being caused to the material; and the material itself must be of a kind that will not be inherently incompatible with treatment in contact with a flame.

Passage of the linear material longitudinally through the flame leads to uniformity of treatment, heat being provided on all sides of a yarn and both sides of a film, tape or fabric. Also, however, such relative direction of travel of the material through the flame ensures that the material passes through the hottest part or parts of the flame.

A single burner is all that is required in the case of treatment of a single travelling yarn. If the linear material is in the form of a fabric, tape or film, however, it may be necessary to arrange a plurality of burners in parallel array, or to provide a wide flat flame from a single burner.

Conveniently, a burner comprises a longitudinally axially-extending tube for passage of the yarn, into which tube gas is supplied through an inlet, the tube being surrounded by a plurality of air holes aerating the flame when lit at the top end of the tube.

The burner is also conveniently provided with a threading-slot for the yarn, extending the whole length of the burner. Closure means for the threading-slot is preferably provided also, to keep out extraneous drafts.

EXAMPLE In one heat treatment process according to the invention, 34 filament yarn of polyhexamethylene adipamide containing 0.3% delustrant was drawn to a denier of 205 on a Barmag draw-winding machine, the cheese wind-up of which was rotated at a speed such as to wind the drawn yarn at 3,600 feet/minute.

Immediately following the departure of the yarn from the drawing zone, the yarn was hot-relaxed by passage longitudinally through and along a gas flame and on to a 10% step-down stepped portion of the draw roll.

The gas flame was provided by a burner having a longitudinally extending threading slot for the yarn, and a closure means therefor. The burner consumed 1 litre per minute of gas, and the flame was aerated in normal fashion.

The hot relaxed yarn had a boiling water shrinkage of about 7%, with its other physical properties being normal.

DRAWINGS The above mentioned burner is illustrated in the drawings, in which FIG. 1 is a longitudinal section through the middle of the burner;

FIG. 2 is a view on AA of FIG. 1, with the threading slot open;

FIG. 3 is another view on AA, with the slot closed;

FIG. 4 is a view on B-B of FIG. 1, showing the closure means for the slot.

In FIG. 1, the longitudinally axially-extending tube 1 for the passage of the yarn is formed at one end of a gas pipe 3 and extends perpendicularly therefrom. The pipe 3 leads into the side of the tube 1. The outlet of tube 1 is surrounded by tubular casing 5, carried by pipe 1. Air is provided in the vicinity of the outlet of tube 1, Where the flame is lit, through holes 7. Lever '9 is provided at the base of the burner, for swivelling the annular member 11 through which the air holes '7 extend, whereby the threading slot 13 for the yarn can be opened or closed, as can be seen more clearly in FIGS. 2, 3 and 4.

Although the invention has been exemplified by reference to a hot-relaxing process on drawn nylon yarn, it will be appreciated that heat treatments of other kinds, such as setting and twist-setting, can be carried out according to the invention on traveling linear material, with considerable gains in throughput speed and compactness of the treating machines.

I claim:

1. In a process for providing a uniform heat treatment to travelling linear material, the improvement comprising passing said material longitudinally through and along a gaseous flame in the direction of flame propagation to distribute heat uniformly around the linear material and to uniformly heat the material and passing said material through said flame at a rate of linear travel high enough to avoid damage to said material.

2. A process according to claim 1 and comprising passing continuous filament yarn longitudinally through and along said gaseous flame whilst allowing said yarn to contract linearly by a predetermined amount.

3. A process as in claim 1 wherein said gaseous flame is generated by introducing combustible gas and combustion-supporting gas into a common zone and igniting the gases in said zone to form a flame extending in the direction of travel of the material being heat treated.

- 4. A process as in claim 3 wherein said streams of gas 4 are introduced into the zone through parallel passageways.

References Cited UNITED STATES PATENTS Re. 19,444 1/1935 Lamplough 26480 2,317,152 4/1943 Costa 264-80 2,746,084 5/1956 Kreidl 264-80 XR 2,795,820 6/1957 Grow 264-80 3,217,074 11/1965 Gould 264-234 XR 3,316,654 5/1967 Gay 264-345 XR FOREIGN PATENTS 729,084 3/ 1966 Canada.

ROBERT F. WHITE, Primary Examiner R. R. KUCIA, Assistant Examiner US. Cl. X.R. 264-235, 346 

